1. Field of the Invention
The present invention relates to telecommunications and, more particularly, to methods and systems for notifying mobile stations of incoming calls.
2. Description of Related Art
A wireless service subscriber who has call waiting is able to receive notification of an incoming call when engaged in a voice call. Typically, the subscriber's mobile station provides an audible indication of the incoming call and visibly displays an identification of the calling party. The subscriber is then able to signal the wireless telecommunications network, such as by pressing the SEND button on the mobile station, to put the first call on hold and connect the incoming call.
Existing call waiting services have significant limitations, however. Call waiting is typically not available when a subscriber is already using call waiting to maintain two calls or when the user is engaged in a three-way call. In particular, because of network and/or mobile station limitations, wireless networks typically limit the number of call legs that a mobile station can maintain at one time. Thus, when a subscriber is using the maximum number of call legs that the wireless network allows, the subscriber will typically not receive any indication if another request to terminate a call to the mobile station comes in.
Call waiting may also be unavailable when the mobile station is involved in an active data session. For example, the CDMA 2000 3G1x standard does not support simultaneous voice and data transmission to the mobile station. As a result, if the mobile station is involved in an active data session it will not receive any notification of incoming voice calls. In other implementations, the mobile station may be able to maintain simultaneous voice calls and active data sessions, albeit up to a maximum number.
Thus, when a mobile station is fully engaged such that it cannot be connected to another call without being disconnected from an existing call (either because it is using all available call legs or because it is involved in an active data session) the mobile station will not be notified of incoming calls. As a result, the user may miss important calls when the user's mobile station is fully engaged. Indeed, the user may not realize that anyone is trying to call him while his mobile station is fully engaged.
Accordingly, there is a need to provide an incoming call notification to mobile stations that are fully engaged.